usr.sbin/rpcbind/util.c

   1 /*-
   2  * Copyright (c) 2000 The NetBSD Foundation, Inc.
   3  * All rights reserved.
   4  *
   5  * This code is derived from software contributed to The NetBSD Foundation
   6  * by Frank van der Linden.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the NetBSD
  19  *      Foundation, Inc. and its contributors.
  20  * 4. Neither the name of The NetBSD Foundation nor the names of its
  21  *    contributors may be used to endorse or promote products derived
  22  *    from this software without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  25  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  26  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  27  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  28  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34  * POSSIBILITY OF SUCH DAMAGE.
  35  *
  36  * $NetBSD: util.c,v 1.4 2000/08/03 00:04:30 fvdl Exp $
  37  * $FreeBSD: src/usr.sbin/rpcbind/util.c,v 1.6 2007/11/07 10:53:39 kevlo Exp $
  38  * $DragonFly$
  39  */
  40
  41 #include <sys/types.h>
  42 #include <sys/socket.h>
  43 #include <sys/queue.h>
  44 #include <net/if.h>
  45 #include <netinet/in.h>
  46 #include <ifaddrs.h>
  47 #include <sys/poll.h>
  48 #include <rpc/rpc.h>
  49 #include <errno.h>
  50 #include <stdlib.h>
  51 #include <string.h>
  52 #include <unistd.h>
  53 #include <netdb.h>
  54 #include <netconfig.h>
  55 #include <stdio.h>
  56 #include <arpa/inet.h>
  57
  58 #include "rpcbind.h"
  59
  60 #define SA2SIN(sa)      ((struct sockaddr_in *)(sa))
  61 #define SA2SINADDR(sa)  (SA2SIN(sa)->sin_addr)
  62 #ifdef INET6
  63 #define SA2SIN6(sa)     ((struct sockaddr_in6 *)(sa))
  64 #define SA2SIN6ADDR(sa) (SA2SIN6(sa)->sin6_addr)
  65 #endif
  66
  67 static struct sockaddr_in *local_in4;
  68 #ifdef INET6
  69 static struct sockaddr_in6 *local_in6;
  70 #endif
  71
  72 static int bitmaskcmp(void *, void *, void *, int);
  73 #ifdef INET6
  74 static void in6_fillscopeid(struct sockaddr_in6 *);
  75 #endif
  76
  77 /*
  78  * For all bits set in "mask", compare the corresponding bits in
  79  * "dst" and "src", and see if they match. Returns 0 if the addresses
  80  * match.
  81  */
  82 static int
  83 bitmaskcmp(void *dst, void *src, void *mask, int bytelen)
  84 {
  85         int i;
  86         u_int8_t *p1 = dst, *p2 = src, *netmask = mask;
  87
  88         for (i = 0; i < bytelen; i++)
  89                 if ((p1[i] & netmask[i]) != (p2[i] & netmask[i]))
  90                         return (1);
  91         return (0);
  92 }
  93
  94 /*
  95  * Similar to code in ifconfig.c. Fill in the scope ID for link-local
  96  * addresses returned by getifaddrs().
  97  */
  98 #ifdef INET6
  99 static void
 100 in6_fillscopeid(struct sockaddr_in6 *sin6)
 101 {
 102         u_int16_t ifindex;
 103
 104         if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
 105                 ifindex = ntohs(*(u_int16_t *)&sin6->sin6_addr.s6_addr[2]);
 106                 if (sin6->sin6_scope_id == 0 && ifindex != 0) {
 107                         sin6->sin6_scope_id = ifindex;
 108                         *(u_int16_t *)&sin6->sin6_addr.s6_addr[2] = 0;
 109                 }
 110         }
 111 }
 112 #endif
 113
 114 /*
 115  * Find a server address that can be used by `caller' to contact
 116  * the local service specified by `serv_uaddr'. If `clnt_uaddr' is
 117  * non-NULL, it is used instead of `caller' as a hint suggesting
 118  * the best address (e.g. the `r_addr' field of an rpc, which
 119  * contains the rpcbind server address that the caller used).
 120  *
 121  * Returns the best server address as a malloc'd "universal address"
 122  * string which should be freed by the caller. On error, returns NULL.
 123  */
 124 char *
 125 addrmerge(struct netbuf *caller, char *serv_uaddr, char *clnt_uaddr,
 126           char *netid)
 127 {
 128         struct ifaddrs *ifap, *ifp = NULL, *bestif;
 129         struct netbuf *serv_nbp = NULL, *hint_nbp = NULL, tbuf;
 130         struct sockaddr *caller_sa, *hint_sa, *ifsa, *ifmasksa, *serv_sa;
 131         struct sockaddr_storage ss;
 132         struct netconfig *nconf;
 133         char *caller_uaddr = NULL, *hint_uaddr = NULL;
 134         char *ret = NULL;
 135
 136 #ifdef ND_DEBUG
 137         if (debugging)
 138                 fprintf(stderr, "addrmerge(caller, %s, %s, %s\n", serv_uaddr,
 139                     clnt_uaddr == NULL ? "NULL" : clnt_uaddr, netid);
 140 #endif
 141         caller_sa = caller->buf;
 142         if ((nconf = rpcbind_get_conf(netid)) == NULL)
 143                 goto freeit;
 144         if ((caller_uaddr = taddr2uaddr(nconf, caller)) == NULL)
 145                 goto freeit;
 146
 147         /*
 148          * Use `clnt_uaddr' as the hint if non-NULL, but ignore it if its
 149          * address family is different from that of the caller.
 150          */
 151         hint_sa = NULL;
 152         if (clnt_uaddr != NULL) {
 153                 hint_uaddr = clnt_uaddr;
 154                 if ((hint_nbp = uaddr2taddr(nconf, clnt_uaddr)) == NULL)
 155                         goto freeit;
 156                 hint_sa = hint_nbp->buf;
 157         }
 158         if (hint_sa == NULL || hint_sa->sa_family != caller_sa->sa_family) {
 159                 hint_uaddr = caller_uaddr;
 160                 hint_sa = caller->buf;
 161         }
 162
 163 #ifdef ND_DEBUG
 164         if (debugging)
 165                 fprintf(stderr, "addrmerge: hint %s\n", hint_uaddr);
 166 #endif
 167         /* Local caller, just return the server address. */
 168         if (strncmp(caller_uaddr, "0.0.0.0.", 8) == 0 ||
 169             strncmp(caller_uaddr, "::.", 3) == 0 || caller_uaddr[0] == '/') {
 170                 ret = strdup(serv_uaddr);
 171                 goto freeit;
 172         }
 173
 174         if (getifaddrs(&ifp) < 0)
 175                 goto freeit;
 176
 177         /*
 178          * Loop through all interfaces. For each interface, see if the
 179          * network portion of its address is equal to that of the client.
 180          * If so, we have found the interface that we want to use.
 181          */
 182         bestif = NULL;
 183         for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
 184                 ifsa = ifap->ifa_addr;
 185                 ifmasksa = ifap->ifa_netmask;
 186
 187                 if (ifsa == NULL || ifsa->sa_family != hint_sa->sa_family ||
 188                     !(ifap->ifa_flags & IFF_UP))
 189                         continue;
 190
 191                 switch (hint_sa->sa_family) {
 192                 case AF_INET:
 193                         /*
 194                          * If the hint address matches this interface
 195                          * address/netmask, then we're done.
 196                          */
 197                         if (!bitmaskcmp(&SA2SINADDR(ifsa),
 198                             &SA2SINADDR(hint_sa), &SA2SINADDR(ifmasksa),
 199                             sizeof(struct in_addr))) {
 200                                 bestif = ifap;
 201                                 goto found;
 202                         }
 203                         break;
 204 #ifdef INET6
 205                 case AF_INET6:
 206                         /*
 207                          * For v6 link local addresses, if the caller is on
 208                          * a link-local address then use the scope id to see
 209                          * which one.
 210                          */
 211                         in6_fillscopeid(SA2SIN6(ifsa));
 212                         if (IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(ifsa)) &&
 213                             IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(caller_sa)) &&
 214                             IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(hint_sa))) {
 215                                 if (SA2SIN6(ifsa)->sin6_scope_id ==
 216                                     SA2SIN6(caller_sa)->sin6_scope_id) {
 217                                         bestif = ifap;
 218                                         goto found;
 219                                 }
 220                         } else if (!bitmaskcmp(&SA2SIN6ADDR(ifsa),
 221                             &SA2SIN6ADDR(hint_sa), &SA2SIN6ADDR(ifmasksa),
 222                             sizeof(struct in6_addr))) {
 223                                 bestif = ifap;
 224                                 goto found;
 225                         }
 226                         break;
 227 #endif
 228                 default:
 229                         continue;
 230                 }
 231
 232                 /*
 233                  * Remember the first possibly useful interface, preferring
 234                  * "normal" to point-to-point and loopback ones.
 235                  */
 236                 if (bestif == NULL ||
 237                     (!(ifap->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) &&
 238                     (bestif->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT))))
 239                         bestif = ifap;
 240         }
 241         if (bestif == NULL)
 242                 goto freeit;
 243
 244 found:
 245         /*
 246          * Construct the new address using the the address from
 247          * `bestif', and the port number from `serv_uaddr'.
 248          */
 249         serv_nbp = uaddr2taddr(nconf, serv_uaddr);
 250         if (serv_nbp == NULL)
 251                 goto freeit;
 252         serv_sa = serv_nbp->buf;
 253
 254         memcpy(&ss, bestif->ifa_addr, bestif->ifa_addr->sa_len);
 255         switch (ss.ss_family) {
 256         case AF_INET:
 257                 SA2SIN(&ss)->sin_port = SA2SIN(serv_sa)->sin_port;
 258                 break;
 259 #ifdef INET6
 260         case AF_INET6:
 261                 SA2SIN6(&ss)->sin6_port = SA2SIN6(serv_sa)->sin6_port;
 262                 break;
 263 #endif
 264         }
 265         tbuf.len = ss.ss_len;
 266         tbuf.maxlen = sizeof(ss);
 267         tbuf.buf = &ss;
 268         ret = taddr2uaddr(nconf, &tbuf);
 269
 270 freeit:
 271         if (caller_uaddr != NULL)
 272                 free(caller_uaddr);
 273         if (hint_nbp != NULL) {
 274                 free(hint_nbp->buf);
 275                 free(hint_nbp);
 276         }
 277         if (serv_nbp != NULL) {
 278                 free(serv_nbp->buf);
 279                 free(serv_nbp);
 280         }
 281         if (ifp != NULL)
 282                 freeifaddrs(ifp);
 283
 284 #ifdef ND_DEBUG
 285         if (debugging)
 286                 fprintf(stderr, "addrmerge: returning %s\n", ret);
 287 #endif
 288         return ret;
 289 }
 290
 291 void
 292 network_init(void)
 293 {
 294 #ifdef INET6
 295         struct ifaddrs *ifap, *ifp;
 296         struct ipv6_mreq mreq6;
 297         unsigned int ifindex;
 298         int s;
 299 #endif
 300         int ecode;
 301         struct addrinfo hints, *res;
 302
 303         memset(&hints, 0, sizeof hints);
 304         hints.ai_family = AF_INET;
 305         if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
 306                 if (debugging)
 307                         fprintf(stderr, "can't get local ip4 address: %s\n",
 308                             gai_strerror(ecode));
 309         } else {
 310                 local_in4 = (struct sockaddr_in *)malloc(sizeof *local_in4);
 311                 if (local_in4 == NULL) {
 312                         if (debugging)
 313                                 fprintf(stderr, "can't alloc local ip4 addr\n");
 314                 }
 315                 memcpy(local_in4, res->ai_addr, sizeof *local_in4);
 316         }
 317
 318 #ifdef INET6
 319         hints.ai_family = AF_INET6;
 320         if ((ecode = getaddrinfo(NULL, "sunrpc", &hints, &res))) {
 321                 if (debugging)
 322                         fprintf(stderr, "can't get local ip6 address: %s\n",
 323                             gai_strerror(ecode));
 324         } else {
 325                 local_in6 = (struct sockaddr_in6 *)malloc(sizeof *local_in6);
 326                 if (local_in6 == NULL) {
 327                         if (debugging)
 328                                 fprintf(stderr, "can't alloc local ip6 addr\n");
 329                 }
 330                 memcpy(local_in6, res->ai_addr, sizeof *local_in6);
 331         }
 332
 333         /*
 334          * Now join the RPC ipv6 multicast group on all interfaces.
 335          */
 336         if (getifaddrs(&ifp) < 0)
 337                 return;
 338
 339         mreq6.ipv6mr_interface = 0;
 340         inet_pton(AF_INET6, RPCB_MULTICAST_ADDR, &mreq6.ipv6mr_multiaddr);
 341
 342         s = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
 343
 344         /*
 345          * Loop through all interfaces. For each IPv6 multicast-capable
 346          * interface, join the RPC multicast group on that interface.
 347          */
 348         for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
 349                 if (ifap->ifa_addr->sa_family != AF_INET6 ||
 350                     !(ifap->ifa_flags & IFF_MULTICAST))
 351                         continue;
 352                 ifindex = if_nametoindex(ifap->ifa_name);
 353                 if (ifindex == mreq6.ipv6mr_interface)
 354                         /*
 355                          * Already did this one.
 356                          */
 357                         continue;
 358                 mreq6.ipv6mr_interface = ifindex;
 359                 if (setsockopt(s, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq6,
 360                     sizeof mreq6) < 0)
 361                         if (debugging)
 362                                 perror("setsockopt v6 multicast");
 363         }
 364 #endif
 365
 366         /* close(s); */
 367 }
 368
 369 struct sockaddr *
 370 local_sa(int af)
 371 {
 372         switch (af) {
 373         case AF_INET:
 374                 return (struct sockaddr *)local_in4;
 375 #ifdef INET6
 376         case AF_INET6:
 377                 return (struct sockaddr *)local_in6;
 378 #endif
 379         default:
 380                 return NULL;
 381         }
 382 }